1. Field
This invention relates to efficient recovery of energy in a DC source-to-grid tie-in. More particularly, it relates to a higher efficiency power extraction paradigm with multiple operational modes.
2. Background
A popular inverter for variable DC power sources is the Neutral Point Clamped inverter (NPC), being recognized as one of the highest efficient inverters in the renewable energy conversion industry. The typical NPC inverter design utilizes offsetting DC boost stages that combine three level voltages (+Vdc/2; 0 V; and −Vdc/2) in a switched manner to achieve a very small ripple current. The DC boost stages power NPC inverter pairs that are “clamped” to a DC bus neutral connection. However, as efficient as the typical NPC inverter design is, as of yet, no consideration has been given to complementing the NPC inverter design with a resonant circuit for more efficient battery charging as well permitting alternative high voltage outputs. Accordingly, solutions to these and other shortcomings in the renewable energy conversion industry using a baseline inverter design, are elucidated in the following description.